For some integrated circuits including a PLL, each voltage controlled oscillator (VCO) in the PLL is tested at the factory for calibration to characterize the available frequency ranges and to predetermine its frequency range setting appropriate for desired output frequencies. When a VCO is selected for a particular application, the appropriate calibration setting is permanently burned into the device, e.g., by blowing fuse links. The factory testing and hard-wiring of the VCO adds to the cost of manufacturing the PLL and also limits the operating frequency range of each PLL to the permanently selected frequency range.